David Emerson was re-elected as Liberal Party MP for the riding of Vancouver-Kingsway, British Columbia, in Canada’s 39th Federal Election on 23 January 2006. Two weeks later, Prime Minister Stephen Harper announced that Mr. Emerson had joined the Conservative Party and appointed him to his cabinet.

The Wikipedia also has a listing of all Canadian politicians who have crossed the floor. The list is incomplete, but including well-known recent floor-crossers such as Mr. Emerson, Belinda Stronach (Wikipedia entry), and Scott Brison (Wikipedia entry).